Go here...
http://support.microsoft.com/default...;en-us;q314058
read all that, check it out.
Hopefully some other more knowledgeable XP guys will respond to this thread shortly.
You can use the recovery console to get access to windows files etc. Then its just a matter of repairing something or possibly deleting some of the bad files....Im not sure if you can uninstall programs from the recovery console.
Here are some of the commands that you may need:
fixmbr
bootcfg/rebuild
Give it a while and let some other guys see this thread...they can expand on what I posted.
like I said, dont do anything rash, this problem is most likely easier to fix than it seems...your data should be safe.
JP